1. Field of the Invention
The present invention relates to a semiconductor component forming a controlled bidirectional switch. More particularly, the present invention provides such a switch capable of withstanding a high current in order, for example, to directly control a load connected to the mains.
2. Discussion of the Related Art
The most commonly known bidirectional switches that are used to control the switching of a.c. currents are triacs which correspond to a parallel, head-to-tail, connection of two thyristors. Triacs, like thyristors, are current controlled. The control currents needed to ensure the triggering of conduction are high, and are substantially higher for triacs than for thyristors. Typical values are several tens of mA. Such high values do not typically allow triacs to be directly controlled by MOS logic circuits.
Moreover, conventional power components provided with control means through MOS-type interfaces, that is, voltage controlled components, are mainly MOS transistors, IGBT, MCT, or analog. The last two components are combinations of control MOS components with bipolar components (bipolar transistors for the IGBTs and thyristors for the MCTs) for the power function.
The above components have drawbacks in that they are unidirectional, which involves the use of a rectifying bridge for operation with a.c. supplies; and their cost per ampere ratio is high, particularly because the surface occupied by MOS-type elements is large with respect to the whole surface of the component.